/Engine/Source/Runtime/Slate/Public/Framework/Application/IInputProcessor.h
Mouse wheel input
virtual bool HandleMouseWheelOrGestureEvent ( [FSlateApplication](API\Runtime\Slate\Framework\Application\FSlateApplication) & SlateApp, const [FPointerEvent](API\Runtime\SlateCore\Input\FPointerEvent) & InWheelEvent, const [FPointerEvent](API\Runtime\SlateCore\Input\FPointerEvent) * InGestureEvent )